The present invention relates to superconductive materials and more particularly to a method for growing and patterning superconductive oxide films represented by the general formula XZ.sub.2 Cu.sub.3 O.sub.6+x, wherein X is yttruim, a lanthanide or a mixture thereof, Z is one or more alkaline earth elements and x is a number between 0 and 1.
There are several problems involved in growing superconductive oxide films such as, for example, YBa.sub.2 Cu.sub.3 O.sub.6+x.
Thin films of the high-Tc superconductivity material YBa.sub.2 Cu.sub.3 O.sub.6+x are difficult to grow because the transport of the elements Y, Ba and Cu in vapor form or in solution is difficult. Some of the reasons for this transport difficulty include:
1. The fact that the elements Y, Ba and Cu or their compounds, and particularly Ba and its compounds, have low vapor pressure.
2. The reactivity of these elements is such that it is difficult to recover them in oxide form. For example, Y reacts with halogens to form very stable oxyhalides.
3. The reactivity of these elements and their compounds at elevated temperatures with boat or ampoule materials leads to contamination of deposited films.
The two most widely investigated techniques for growing thin films of YBa.sub.2 Cu.sub.3 O.sub.6+x with a minimum of contamination are sputtering and evaporation. The layer quality of sputtered or evaporated films has not been good because of the lack of uniformity in the deposited layers. This non-uniformity is caused by the non-uniformity of vapor compositions, as well as by differences in the vapor pressure and sticking coefficients for the various elements.
It should be noted that contamination and/or nonuniformity of the superconductive material YBa.sub.2 Cu.sub.3 O.sub.6+x can lower the Tc of that resultant superconductive material or even prevent the superconductive phase of that material from forming.
In addition to the problems involved in growing the high-Tc superconductivity material YBa.sub.2 Cu.sub.3 O.sub.6+x, there is the further difficulty of patterning this superconducting material YBa.sub.2 Cu.sub.3 O.sub.6+x.
Therefore, there is a need to deliver intimately mixed stoichiometric ratios of the aforesaid X, Z.sub.2 and Cu.sub.3 components of the aforesaid general formula XZ.sub.2 Cu.sub.3 O.sub.6+x to a reaction site, such as a substrate, to minimize non-uniformity of the thin film XZ.sub.2 Cu.sub.3 O.sub.6+x, and to also grow patterned thin film XZ.sub.2 Cu.sub.3 O.sub.6+x in order to provide superconducting interconnects or conductors with a minimum of contamination from either transport agents or container materials.